1. Technical Field
The document relates to a display device and a method of displaying an image of a pixel, especially a method of transforming image data of the signal values corresponding to the three primary colors into image data of the signal values corresponding to the three primary colors and the white color.
2. Description of the Prior Art
Liquid crystal displays (LCDs) and light emitting diode (LED) displays are widely used nowadays. Because liquid crystal displays and LED displays have slim shapes, low power dissipation and low radiation, liquid crystal displays and LED displays gradually replace traditional CRT (cathode ray tube) monitors and are widely used in mobile electronic devices such as notebooks and PDAs (personal digital assistants).
Compared to LCDs, organic light emitting diode (OLED) displays are capable of self-emitting light and have wider viewing angles, higher contrast, lower operating voltages, faster dynamic response, brighter colors, simpler manufacturing processes and thinner thickness, thus they are gradually replacing LCDs. In OLED display manufacturing procedures, a bias voltage is applied to an OLED, to make the inner electrons and electric holes pass through the hole transport layer and the electron transport layer, then an organic material capable of emitting light is added to the OLED. Afterwards excitons will be formed, energy will be released and excitons will return to the ground state. The energy can be released in various colored light, and the color is determined by the characteristic of selected organic materials.
The prior OLED displays are usually equipped with light emitting elements of red, green and blue colors to display high luminance and high chrominance images. However, the lifespan of red, green and blue light emitting elements is different, causing the displays to display incorrect colors due to the attenuation of the light emitting elements.
To solve the above issue, white OLEDs formed with RGB color filters have been developed. However, the RGB color filters will reduce the penetration rate of the display. To solve this problem, four color OLEDs with color filters of red, green, blue and white have been proposed. The prior four color OLEDs utilize the high penetration rate of white color to enhance the luminance of the display. But images displayed by the four color OLEDs still have color distortion, and power dissipation can not be effectively reduced.